— 192 — 
that by counting the numbers of drops which fall from any 
two spheres in the same time, we get at once the relative sizes 
of the respective drops. For several reasons this plan of 
comparison is not sufficiently accurate to measure drop sizes, 
but it offers a method for making the difference of drop size 
visible to any number of persons at once. 
The only other variation in the geometrical relation be* 
tween the solid and the liquid which we shall consider is the 
variation in the size of a circular horizontal plane from which 
drops fall. 
• g A Q 
Five discs of copper foil were cut of the radii '20 ^0 
2 1 \ 
— ^ ~ , of an inch respectively. These were fastened hori- 
zontally to vertical wires and having been thoroughly cleaned 
by momemtary immersion in nitric acid and washing, water 
• was made to drop from them as before, at the rate gt.— 2 ” 
Table X shows the influence of this kind of variation upon 
drop size. The want of accord in the numbers of the largest 
disc is owing to a peculiar tremor which the drops exhibit at 
the moment of delivery. The same phenomenon occured also 
but to a less extent with the next smaller disc. With the VC' 
mainder it was not noticeable. 
